UPDATE: At a standup press conference on the campaign trail, Mr Key confirmed several of his senior staff would appear in front of the Inspector-General of Intelligence and Security's inquiry.

Asked whether he would appear, the PM said, "Apparently not. there's a bit of confusion there."

However, a spokeswoman for the PM's office later issued a statement saying "There was no indication in the letter [from the IG] that the Prime Minister would be called personally and the Prime Minister's office is not aware that would be the case. In terms of Prime Minister's office staff, no date was given in the letter for the interviews to take place."

Labour leader David Cunliffe has called for a Royal Commission of Inquiry to restore public confidence. Mr Key said his case was "rock solid". He did not think the allegations were at a level that justified a Royal Commission.

The notices sent by the Inspector-General include a reminder that anyone who ignores her summons is liable on conviction to a fine of up to $5000.

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EARLIER: Cameron Slater has been summoned to face Inspector-General of Intelligence and Security Cheryl Gwyn on September 11.

Rumours have been circulating this afternoon that a number of figures in the Dirty Politics saga have received notices requiring them to appear for a pre-election grilling.

A Fairfax report says Prime Minister John Key plus several senior members of his office including chief-of-staff Wayne Eagleson, OIA specialist Sarah Boyle and former staffer Jason Ede are understood to have also received a summons.

Mr Slater is the first to go on record confirming to NBR he has received a formal notice requiring him to meet with the IG.

The notice was issued under Section 23 of the Inspector-General of Intelligence and Security Act (1996).

On August 22, Ms Gwyn opened an investigation into the unusually rapid turnaround of SIS documents to Mr Slater following an Official Information Act request from the Whale Oil blogger in July 2011.

The IG is seeking to establish whether the SIS documents were declassified and released to Mr Slater "in order to be used for political purposes".

There have also been questions over whether then SIS head Dr Warren Tucker directly informed Prime Minister John Key about the release of the documents, which were embarrassing to then Labour leader Phil Goff. Mr Key and Dr Tucker both say a direct briefing did not take place, but that the PM's office was updated.

Questions have also been asked over whether Mr Slater was directed by government ministers or their aides to make specific OIA requests (something the Whale Oil blogger and his government contacts deny).

On August 22, Mr Key said he was comfortable with the IG accessing his staff's email as part of her investigation. He also told media that he was on holiday in Hawaii at the time his office was briefed on the release of the documents to Mr Slater. Asked if he could have been briefed by phone, Mr Key said he was happy to open his phone records to any inquiry.

The IG is not expected to report back on her investigation until well after the election.

Separately, also on August 22, Chief Ombudsman Dame Beverley Wakem said she would open an investigation into the way the Official Information Act is used.